The present invention relates to an eyeglass lens processing apparatus which processes an eyeglass lens.
In an eyeglass lens processing apparatus, an eyeglass lens is rotated while being held (chucked) by two lens chucking shafts, and the periphery of the lens is processed by a processing tool such as a grindstone so as to substantially conform to a desired target lens shape. The holding of the lens is performed by fixedly attaching a cup serving as a fixture to the rear refractive surface of the lens by suction, adhesion, or the like, mounting the cup to which the lens is fixed to a cup receiver at a distal end of the one chucking shaft, and allowing a lens presser at a distal end of the other chucking shaft to abut on the lens.
When the periphery of the lens is processed with the processing tool which rotates at high speed, if a load exceeding the holding force of the lens is applied to the lens, rotational deviation may occur between the cup and the lens, and thereby so-called axis deviation may occur. In particular, in a liquid-repellent lens whose surface is coated with a liquid-repellant substance to which water, oil, or the like does not stick easily, the possibility of occurrence of axis deviation is high because the surface slips readily.